diff --git a/flake.nix b/flake.nix
index 6dd9c66a..2dfd754e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,6 +1,11 @@
 {
   description = "C3D2 NixOS configurations";
 
+  nixConfig = {
+    extra-substituters = [ "https://nix-serve.hq.c3d2.de" ];
+    extra-trusted-public-keys = [ "nix-serve.hq.c3d2.de:KZRGGnwOYzys6pxgM8jlur36RmkJQ/y8y62e52fj1ps=" ];
+  };
+
   inputs = {
     # use sandro's fork full with cherry-picked fixes
     nixos.url = "github:SuperSandro2000/nixpkgs/nixos-22.11";